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-~ <br />He faxed the pages of his log book to me on Friday, October 22, 2004. The notes indicate that <br />the well was purged for 7 minutes. Per my calculations, a minimum of ten minutes is required to <br />purge the minimum 3 casing volumes specified in the CDPHE GW sampling protocol. <br />Tri-County Health <br />Dan Collins, (720)322-1520, fax: (720)322-1500 <br />Per a telephone conversation with Dan Collins on Tuesday, October 19, 2004, Tri-County Health <br />samples the private wells, and the Army samples the monitoring wells. They collect 1 liter <br />samples, use no preservatives, and fill the bottles full (no air) to ensure no volatilization of volatile <br />sampling constituents (DIMP is not volatile, but semi-volatile). Since they often do not know the <br />volumes of the well borings to determine when "three volumes" have been purged, they run each <br />well for 45 minutes prior to sampling, and sample the well each 9 minutes until parameters such <br />as pH, conductivity, and temperature indicate the well water is stable. Where possible, they then <br />reduce the Flow to about %gallon-per-minute to collect the sample. <br />Per his instruction, on Wednesday, October 20, 2004, I faxed a request for a copy of their work <br />plan with respect to sampling. The Work Plan section was faxed tc me by George Rathbun <br />[(720)322-1525], and I received it Thursday, October 21, 2004. I would like to see these <br />procedures followed, to the extent they apply. <br />George Rathbun contacted me on Tuesday, October 26, 2004, to check if I had received his fax, <br />to learn our purposes, and to ask that we contact them if samples show detectable DIMP, esp. <br />above 8 ppb (µg/L). He thought he remembered the objectors and their concerns, adding that <br />Tri-County, though generally liberal in their willingness to sample if requested, thought this site <br />was out of their area of concern, sc they did not sample for them. When they sample at <br />dewatering gravel pits, it is at their discharge to the South Platte River. <br />They currently are mostly focusing near 112th Avenue. Recent sampling will likely lead to <br />removing the "nose" of the plume from the maps. <br />He stated the adsorbed to soil theory is possible; however, his thought was that if it were to <br />happen, it would occur near the plume, and not as removed from the plume as these sites. <br />.... <br />Being highly soluble, it follows that if the DIMP were present (e.g. adsorbed to soil) below water <br />table, it would already be in the ground water and no extraction activities would be necessary to <br />liberate it. Sampling by the arsenal confirms it is not present at levels of concern in the area of <br />the Topper property or AM#1. <br />3 <br />